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freebsd/sys/dev/iicbus/pcf8563.c
Marius Strobl f9e26776a6 It turns out that as documented, PCF8563_R_SECOND_VL (i.e. battery low)
doesn't automatically clear when VDD rises above Vlow again and needs to be
cleared manually. However, apparently this needs all of the time registers
to be set, i.e. pcf8563_settime(), and not just PCF8563_R_SECOND in order
for PCF8563_R_SECOND_VL to stick. Thus, we just issue a warning during
pcf8563_attach() rather than failing with ENXIO in case it is set.

MFC after:	3 days
2012-10-18 10:29:16 +00:00

211 lines
6.5 KiB
C

/*-
* Copyright (c) 2012 Marius Strobl <marius@FreeBSD.org>
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
/*
* Driver for NXP PCF8563 real-time clock/calendar
*/
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/bus.h>
#include <sys/clock.h>
#include <sys/kernel.h>
#include <sys/module.h>
#include <dev/iicbus/iicbus.h>
#include <dev/iicbus/iiconf.h>
#include <dev/iicbus/pcf8563reg.h>
#include "clock_if.h"
#include "iicbus_if.h"
#define PCF8563_NCLOCKREGS (PCF8563_R_YEAR - PCF8563_R_CS1 + 1)
struct pcf8563_softc {
uint32_t sc_flags;
#define PCF8563_CPOL (1 << 0) /* PCF8563_R_MONTH_C means 19xx */
uint16_t sc_addr; /* PCF8563 slave address */
uint16_t sc_year0; /* TOD clock year 0 */
};
static device_attach_t pcf8563_attach;
static device_probe_t pcf8563_probe;
static clock_gettime_t pcf8563_gettime;
static clock_settime_t pcf8563_settime;
static int
pcf8563_probe(device_t dev)
{
device_set_desc(dev, "NXP PCF8563 RTC");
return (BUS_PROBE_NOWILDCARD);
}
static int
pcf8563_attach(device_t dev)
{
uint8_t reg = PCF8563_R_SECOND, val;
struct iic_msg msgs[] = {
{ 0, IIC_M_WR, sizeof(reg), &reg },
{ 0, IIC_M_RD, sizeof(val), &val }
};
struct pcf8563_softc *sc;
int error;
sc = device_get_softc(dev);
sc->sc_addr = iicbus_get_addr(dev);
if (sc->sc_addr == 0)
sc->sc_addr = PCF8563_ADDR;
/*
* NB: PCF8563_R_SECOND_VL doesn't automatically clear when VDD
* rises above Vlow again and needs to be cleared manually.
* However, apparently this needs all of the time registers to be
* set, i.e. pcf8563_settime(), and not just PCF8563_R_SECOND in
* order for PCF8563_R_SECOND_VL to stick. Thus, we just issue a
* warning here rather than failing with ENXIO in case it is set.
* Note that pcf8563_settime() will also clear PCF8563_R_SECOND_VL
* as a side-effect.
*/
msgs[0].slave = msgs[1].slave = sc->sc_addr;
error = iicbus_transfer(device_get_parent(dev), msgs, sizeof(msgs) /
sizeof(*msgs));
if (error != 0) {
device_printf(dev, "%s: cannot read RTC\n", __func__);
return (error);
}
if ((val & PCF8563_R_SECOND_VL) != 0)
device_printf(dev, "%s: battery low\n", __func__);
sc->sc_year0 = 1900;
clock_register(dev, 1000000); /* 1 second resolution */
return (0);
}
static int
pcf8563_gettime(device_t dev, struct timespec *ts)
{
struct clocktime ct;
uint8_t reg = PCF8563_R_SECOND, val[PCF8563_NCLOCKREGS];
struct iic_msg msgs[] = {
{ 0, IIC_M_WR, sizeof(reg), &reg },
{ 0, IIC_M_RD, PCF8563_NCLOCKREGS, &val[PCF8563_R_SECOND] }
};
struct pcf8563_softc *sc;
int error;
sc = device_get_softc(dev);
msgs[0].slave = msgs[1].slave = sc->sc_addr;
error = iicbus_transfer(device_get_parent(dev), msgs, sizeof(msgs) /
sizeof(*msgs));
if (error != 0) {
device_printf(dev, "%s: cannot read RTC\n", __func__);
return (error);
}
ct.nsec = 0;
ct.sec = FROMBCD(val[PCF8563_R_SECOND] & PCF8563_M_SECOND);
ct.min = FROMBCD(val[PCF8563_R_MINUTE] & PCF8563_M_MINUTE);
ct.hour = FROMBCD(val[PCF8563_R_HOUR] & PCF8563_M_HOUR);
ct.day = FROMBCD(val[PCF8563_R_DAY] & PCF8563_M_DAY);
ct.dow = val[PCF8563_R_WEEKDAY] & PCF8563_M_WEEKDAY;
ct.mon = FROMBCD(val[PCF8563_R_MONTH] & PCF8563_M_MONTH);
ct.year = FROMBCD(val[PCF8563_R_YEAR] & PCF8563_M_YEAR);
ct.year += sc->sc_year0;
if (ct.year < POSIX_BASE_YEAR)
ct.year += 100; /* assume [1970, 2069] */
if ((val[PCF8563_R_MONTH] & PCF8563_R_MONTH_C) != 0) {
if (ct.year >= 100 + sc->sc_year0)
sc->sc_flags |= PCF8563_CPOL;
} else if (ct.year < 100 + sc->sc_year0)
sc->sc_flags |= PCF8563_CPOL;
return (clock_ct_to_ts(&ct, ts));
}
static int
pcf8563_settime(device_t dev, struct timespec *ts)
{
struct clocktime ct;
uint8_t val[PCF8563_NCLOCKREGS];
struct iic_msg msgs[] = {
{ 0, IIC_M_WR, PCF8563_NCLOCKREGS - 1, &val[PCF8563_R_CS2] }
};
struct pcf8563_softc *sc;
int error;
sc = device_get_softc(dev);
val[PCF8563_R_CS2] = PCF8563_R_SECOND; /* abuse */
/* Accuracy is only one second. */
if (ts->tv_nsec >= 500000000)
ts->tv_sec++;
ts->tv_nsec = 0;
clock_ts_to_ct(ts, &ct);
val[PCF8563_R_SECOND] = TOBCD(ct.sec);
val[PCF8563_R_MINUTE] = TOBCD(ct.min);
val[PCF8563_R_HOUR] = TOBCD(ct.hour);
val[PCF8563_R_DAY] = TOBCD(ct.day);
val[PCF8563_R_WEEKDAY] = ct.dow;
val[PCF8563_R_MONTH] = TOBCD(ct.mon);
val[PCF8563_R_YEAR] = TOBCD(ct.year % 100);
if ((sc->sc_flags & PCF8563_CPOL) != 0) {
if (ct.year >= 100 + sc->sc_year0)
val[PCF8563_R_MONTH] |= PCF8563_R_MONTH_C;
} else if (ct.year < 100 + sc->sc_year0)
val[PCF8563_R_MONTH] |= PCF8563_R_MONTH_C;
msgs[0].slave = sc->sc_addr;
error = iicbus_transfer(device_get_parent(dev), msgs, sizeof(msgs) /
sizeof(*msgs));
if (error != 0)
device_printf(dev, "%s: cannot write RTC\n", __func__);
return (error);
}
static device_method_t pcf8563_methods[] = {
DEVMETHOD(device_probe, pcf8563_probe),
DEVMETHOD(device_attach, pcf8563_attach),
DEVMETHOD(clock_gettime, pcf8563_gettime),
DEVMETHOD(clock_settime, pcf8563_settime),
DEVMETHOD_END
};
static driver_t pcf8563_driver = {
"pcf8563_rtc",
pcf8563_methods,
sizeof(struct pcf8563_softc),
};
static devclass_t pcf8563_devclass;
DRIVER_MODULE(pcf8563, iicbus, pcf8563_driver, pcf8563_devclass, NULL, NULL);
MODULE_VERSION(pcf8563, 1);
MODULE_DEPEND(pcf8563, iicbus, 1, 1, 1);